Safety guards are commonly used in many applications where a human operator must be shielded from moving machinery. The specific configuration of these guards varies, depending upon the particular application for which the guard is used.
In the fields of textile manufacturing and the processing and manufacture of both natural and man-made fibers, the use of units including rotating godet rollers (also referred to as godet wheels or godets) is common. A godet unit typically includes one or more upper godet rollers and one or more lower godet rollers which rotate in different directions. A bundle of fibers is entrained around the godet rollers and from one roller to the next. In the area where the fibers initially contact the rotating godet roller, a "nip" or pinch point is formed. The godet rollers are frequently operated at relatively high speeds for quality and efficiency purposes and consequently a need exists to prevent inadvertent contact with the rollers and fibers, which may lead to entrainment of an object in the fibers and about the godet rollers.
During the processing of the fibers by the godet unit, it is common for one or more of the fibers to break regardless of the processing speed. The broken fibers will often separate from the other fiber and begin to wrap around one of the godet rollers. If left unattended, the "wrap" will build up on the godet roller, ultimately requiring that the processing line be shut down for a period of time, until the roller can be cleared of the wrap. Conversely, if the wrap is severed shortly after it begins, the severed fiber will rejoin the other fiber and proceed through the remainder of the processing line.
The frequency of occurrence of wraps in synthetic fiber processing depends upon a number of factors, including but not limited to atmospheric humidity, processing temperature and the type of raw materials from which the fibers are being manufactured. It is common for wraps to occur as frequently as once every ten minutes. The nature of the fiber processing line is such that it should not be stopped and started abruptly. The line must be gradually brought to a halt, and upon restarting, the speed of the line is gradually increased until full processing speed is attained. The time required to stop the line to cut a wrap and bring it back up to full speed is ten to fifteen minutes, and during the restarting, additional wraps may be generated.
The safety guards currently available with godet units include a solid transparent shield. While the currently available shields allow an operator to see when a wrap has started, they prevent the operator from cutting the wrap while the shield is in position. Because of the significant amount of down time caused by stopping the line, it has become standard practice in the industry for operators to reach into the godet unit to cut a wrap while the godet rollers are operating.
Another existing safety mechanism is a shut-off cable which is suspended along the length of the godet unit, between the operator and the godet rollers. In the event an operator falls or is pulled toward the godet rollers, the weight of his or her body against the cord activates a mechanism to stop the rotation of the godet rollers. While it is possible that this safety mechanism may limit the extent of an operator's injuries, it is ineffective as a measure to prevent entrainment.
While it is quite common in the industry for properly trained operators to safely cut wraps with tools such as utility knives, a need exists in the industry for a safety apparatus that will allow operators of a godet unit to cut a wrap from an operating godet roller, while reducing the risk of the operator or his tools being caught and drawn into the godet rollers.